The latest edition of the archaeology journal, Antiquity (Volume 81 No. 313 September 2007, link to summary) contains an article by Mike Parker Pearson et al entitled “The age of Stonehenge”. It is a summary of progress so far on the Stonehenge Riverside Project and the Beaker isotope project, and contains some interesting and important revelations about the Stonehenge and its landscape.
It is now thought that the trilithons were erected not circa 2300 BCE, but between 2600-2400 cal BCE, making them contemporary with Durrington Walls. They now predate the earliest Beaker burials in Britain, shaking our understanding of the late Neolithic and early Bronze Age.
Unfortunately, unless you have access to a library or institution that subscribes to Antiquity in hard copy, you’ll have to pay £15 to download a PDF of the article. I’m sure it won’t be long before some of the key points are available online, with a little bit of luck.